The invention relates to a measuring system for detecting variables on planet carriers of a planetary gear train comprising at least multiple planetary gear stages, wherein each planetary gear stage comprises at least one respective sun shaft, at least one respective ring gear, and also at least one respective planet gear which is connected to the respective sun shaft and the respective ring gear by a toothed engagement, and a respective planet carrier which is assigned to the at least one planet gear and is rotationally connected to the at least one planet gear.
Planetary gear trains offer clear advantages in terms of power density and specific torque as compared with conventional spur gear and bevel spur gear trains, and comprise a sun shaft, a planet carrier with planet gears, and also an internally toothed ring gear. Due to a basic cylindrical shape of the ring gears, planetary gear trains for industrial applications frequently have a cylindrical construction. Planetary gear trains can be installed as slip-fit gear trains with a torque support, as bolt-on or flange-connected gear trains, or mounted on a base with an additional frame.
In gear trains, in particular wind power gear trains, bearings represent one of the most frequent causes of failure. The most diverse sensors and measuring systems are employed for monitoring and assessing these bearings.
In evaluating the signals recorded by the sensors, the transmission path from the signal source to the sensor is of critical importance.
Among the most diverse gear train types, in particular multistage planetary gear trains, i.e. with more than one planetary gear stage, a large number of the bearings can still only be monitored poorly or with substantial effort according to the state of the art, since these bearings are situated in a coordinate system that is rotating as compared with the environment.
Different states of the art exist for the different sensor types and evaluations. Thus pressure, temperature, and vibration/acceleration measuring sensors are generally mounted in the form of “static” sensors in the fixed coordinate system. However there is no associated option for monitoring the rotating planet gears of the various stages of a planetary gear train in a rotating manner. In particular rotating monitoring of the second or third or following stages respectively of a planetary gear train has not been possible up to now.
In determining the torque, so-called “telemetry” sensors are generally mounted in the rotating coordinate system. However these systems need energy. The energy supply is either designed via slip rings or e.g. via a battery. However this is not designed for the lifetime.